1. Field of the Disclosure
This disclosure generally relates to an optical navigation system and, more particularly, to an optical navigation module capable of performing the lateral detection and adjusting the tracking distance.
2. Description of the Related Art
A basic opto-mechanical construction of an optical navigation system consists of a sensor mated with a lens, wherein a navigation surface is substantially parallel to a mounting plane of the sensor. The optical navigation system further consists of an illuminator to illuminate an area of interest on the navigation surface, but there is generally less constraints on a mounting direction of the illuminator with respect to the navigation surface.
In some cases, it is desired to track a surface or an object that is at an angle (not parallel) to a main board of the optical navigation system. In such cases, since current optical navigation solutions are limited to track surfaces parallel to a sensor plane, the sensor has to be mounted at a desired angle relative to the main board. FIG. 1 shows an existing solution in which a sensor 95 is mounted on a separate printed circuit board (PCB) 93, which is connected to a main board 91 at an angle, via a right-angle connector 97. However, this solution requires increased handling as well as additional costs (e.g. for the separate PCB 93, right-angle connector 97, assembly, etc.). In addition, this solution occupies significant amount of space.
Another characteristic of current optical navigation solutions is that a nominal tracking distance from the sensor to the navigation surface is fixed. The optical system design may accord some deviations from this nominal tracking distance, but this is usually limited to about +/−0.3 mm and typically would carry some penalty in degraded performance.